Injection device

ABSTRACT

The invention relates to an injection device for injecting a selectable dose of a liquid substance from an ampoule, located in an ampoule holder, comprising a piston and a sleeve-shaped mechanism holder, mechanically coupled thereto, in the interior of which a longitudinally shiftable shaft is provided which acts on the ampoule.

RELATED APPLICATIONS

This is a Continuation Application of U.S. application Ser. No.08/983,553, filed on Jun. 18, 1999, now issued as U.S. Pat. No.6,277,101, issued on Aug. 21, 2001, which claims priority toPCT/CH96/00115, filed on Apr. 2, 1996, both of which are incorporated byreference herein.

BACKGROUND

The invention relates to an injection device for injecting a selectabledose of a liquid substance from an ampoule located in an ampoule holder,comprising a sleeve-shaped mechanism holder mechanically coupledthereto, in the interior of the mechanism holder a longitudinallyshiftable shaft with a piston disposed thereon being provided which actson the ampoule, wherein the shaft being surrounded by an alsolongitudinally shiftable advancing sleeve, mechanically coupled thereto,which in its upper end area is closed by a lid.

Such an injection device is known from EP 0 373 321 B 1 that consists ofan ampoule sleeve for receiving the ampoule and a delivering mechanism.In turn, this is composed of a cylindrical piston shaft with an innerhollow cylinder and an outer hollow cylinder which is formed in onepiece with this and which exhibits a guiding cam on its outer shell. Adosing ring is fixed radially to the outer hollow cylinder. The dosingcan be read off by means of a scaling fastened to the outer perimeter ofthe dosing ring through a sight glass set into the housing of themechanism holder. The delivering mechanism is disposed longitudinallymovably in the mechanism holder by means of a retaining spring andsecured by a lid screwable into the housing of the mechanism holder. Thedosing ring rests against the lid with the force of the retainingspring. The housing of the mechanism holder is provided on its insidewith elongated slots of different length in which the correspondingguiding cam of the delivering mechanism is able to glide. As a result,the lift of the delivering mechanism is determined by the length of theelongated slot cooperating with the guiding cam. The adaptation of thedose to be administered to the needs of a patient takes placeexclusively by an authorized person, e. g. a physician. Aspecial-purpose wrench is necessary, by means of which an interlockingring of the device can be unlocked until the guiding cam of thedelivering mechanism is released from the respective elongated slot. Thephysician is then able to select the desired dose by rotation of thereleased delivering mechanism and renewed catch of the guiding cam intoa corresponding elongated slot.

Once selected, the dose cannot be varied without considerable effort. Inaddition, based on the construction of the delivering mechanism, theinjection device can only be used for delivering a single dose althoughpossibly a sufficient supply of medicine is still available in theampoule. In order to administer another dose of medicine, the ampoulesleeve must be unlocked from the mechanism holder and disposed oftogether with the ampoule possibly still containing medicine.

An injection device of generic type is known from EP 0 037 696 B 1 withwhich a dose of a liquid substance to be administered can be taken froman ampoule via a transmission mechanism of tractive force acting in onedirection upon operating a locking cap. The transmission mechanism oftractive force consists in that one pushing part is equipped with aplurality of teeth and the other pushing part with a pawl, whichintermesh and therefore effect the advance of the transmission mechanismof tractive force only in one direction of ejection of the dose to beadministered. The maximum lift height and therefore the maximum dose tobe administered is limited via a notch and a stop. The operator of theinjection device is also able to select less than the maximum dose bylistening to the number of clicks which occur when, during the advance,the teeth of the pushing part catch in the pawl. In this connection, oneclick corresponds to the minimum dose. The operating element, thelocking cap, is pushed back up to a stop by means of a spring.

This injection device is designed for extremely careful operation sincea click can easily be overheard and different doses to be administerednot be securely adjusted. In addition, no display unit is foreseen forthe dose to be selected.

SUMMARY

The present invention is therefore based on the problem to identify aninjection device of the type described above which is simple in theconstructive design and simple in the handling and with which theoperator himself by simple movements is safely able to select the doseto be administered.

This problem is thereby solved in that a dosing sleeve with a steppedmember is provided for selecting a dose of a liquid substance to beinjected, which is disposed on the mechanism holder in its upper endarea, wherein the dose to be respectively administered being adjustableby a rotation of the dosing sleeve with the stepped member.

In this case, the dosing sleeve is composed of an operating element witha profile, an adjoining cylinder with dose imprint, a catch stop, andthe stepped member adjoining this. The constructive coupling of thedosing sleeve to the injection device is thereby characterized in thattogether with the stepped member and the cylinder with the dose imprintit surrounds the advancing sleeve.

The injection device according to the invention has the fundamentaladvantage that a dose, adjusted once, can be applied repeatedly; theuser just has to load the injection device before each injection. Theselection of the dose to be applied is quite easy due to a simplerotation of the dosing sleeve.

Further advantageous embodiments of the invention can be taken from thedependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention is represented in the FIGS.

It is shown in:

FIG. 1: the injection device according to the invention in section;

FIG. 2: the dosing sleeve with stepped member in a perspective view;

FIG. 3: a section along the line A—A in FIG. 1.

DETAILED DESCRIPTION

The injection device shown in FIG. 1 consists of the ampoule holder 1 inwhich the ampoule 2 with the piston 12 and with the liquid substance tobe administered are located. The sleeve-shaped mechanism holder 3 ismechanically coupled to the ampoule holder 1 by a thread or anothersuitable lock such as a bayonet lock. In the interior of the mechanismholder 3, the longitudinally shiftable shaft 4 is disposed acting on thepiston 12 of the ampoule 2. The shaft 4 is surrounded by the alsolongitudinally shiftable advancing sleeve 5 mechanically coupledthereto, which is closed in its upper end area by the lid 7. Forselecting a dose of the liquid substance to be injected, the dosingsleeve 6 with the stepped member 13 is provided which is arranged on themechanism holder 3 in its upper end area. In this case, the dosingsleeve 6 with the stepped member 13 surrounds the advancing sleeve 5.The dose to be respectively adjusted and to be administered isselectable by a simple rotation of the dosing sleeve 6 with the steppedmember 13. The dosing sleeve 6 is mechanically coupled to the mechanismholder 3 via the catch stop 14. The dosing sleeve 6 consists, accordingto FIG. 2, of the profiled operating element 16, the adjoining cylinder15 with the dose imprint, the catch stop 14, and the stepped member 13adjoining this. The cam 8 is disposed on the advancing sleeve 5, whichupon withdrawing the advancing sleeve 5 in the direction of the lid 7comes to a stop against the step of the stepped member 13 respectivelyadjusted. Upon pressing down the advancing sleeve 5, the cam 8 comes toa stop against the shoulder 18 of the mechanism holder 3, resulting inthe injection lift X.

For mechanical coupling of shaft 4 with the advancing sleeve 5 the shaft4 is provided with the toothing 17 which cooperates with the locking cam10 of the advancing sleeve 5. In this case, the depth of tooth of thetoothings 17 on the shaft 4 corresponds to the step height of thestepped member 13. In the area of its lower end, the mechanism holder 3comprises the catch 11 which also cooperates with the toothing 17 of theshaft 4. The dose imprint on the cylinder 15 is visible via a window 9in the mechanism holder 3. In its interior, the mechanism holder 3comprises a plurality of bulges 19 into which the projections 20 of thestepped member 13 catch. (FIG. 3) The shaft 4 is non-rotatablylongitudinally shiftable.

The mode of operation of the injection device according to the inventionis as follows:

The operator turns the dosing sleeve 6 with the stepped member 13 untilthe desired dose imprint on the cylinder appears in the window 9. Then,the injection device is loaded. FIG. 1 shows this before the loading.For the loading, the advancing sleeve 5 is pulled upward by the lid 7,mechanically coupled thereto, until the cam 8 which is part of theadvancing sleeve 5 comes to a stop against the currently adjusted stepof the stepped member 13. In this case, the locking cam 10 of theadvancing sleeve 5 glides over the toothing 17 of the shaft 4, the teethof which (not shown) are arrow-shaped downward. In order to prevent thatthe shaft 4 is nevertheless shifted upward at the same time, the catch11 is provided on the mechanism holder 3 which is not shiftablelongitudinally. Thus, the catch 11 braces itself into the toothing 17and prevents motion of the shaft 4 upward. For administering theselected dose, pressure in the downward direction is exerted by theoperator on the lid 7 and on the advancing sleeve 5 coupled thereto. Inthis case, the locking cam 10 braces itself into the toothing 17 and, soto say, takes the shaft 4 along and the piston 12 coupled to the shaft 4exerts pressure on the ampoule 2 located in the ampoule holder 1, withwhich the liquid substance is applied by administering it through aninjection needle (not shown). Upon pressing down the advancing sleeve 5by means of the lid 7, the teeth of the toothing 17 also glide over thecatch 11 of the mechanism holder 3, wherein the catch 11 is out of meshby means of the selected arrow-shape of the teeth of the toothing 17.The advance motion of the advancing sleeve 5 in the downward directionlasts until the cam 8 comes to a stop against the shoulder 18 of themechanism holder 3 so that the selected dose of the liquid substance isadministered. The injection device is prepared by renewed loading forone or more subsequent injections. The shaft 4 remains during theloading processes in the immediately before-given state by means of thetoothing of catch 11 with the teeth of toothing 17. In particular, theshaft moves only in one direction, that is so to say downward, while theadvancing sleeve lets itself move in two directions, so to say upwardfor loading and downward for applying. The injection device according tothe invention can serve for the administering of medicine. However, itis also possible to administer lotions and other liquid substances withit.

The length of the injection lift X is determined by the individualdifferences of the steps of the stepped member 13 such that with anampoule 2 with a specific diameter X is an integral multitude of a doseunit.

What is claimed is:
 1. An injection device for injecting a selectabledose of a substance, the injection device comprising: a longitudinallyshiftable shaft, said shaft carrying notches, each notch having a depth;an advancing sleeve surrounding the shaft, wherein the advancing sleeveis slidably connected to the shaft to permit the shaft to move in onedirection relative to the advancing sleeve, said advancing sleevecarrying a stop and a locking cam, said cam mating with the notches; anda dosing sleeve partially surrounding the advancing sleeve, the dosingsleeve having radially dispersed steps, each having a longitudinallength corresponding to the depth of one of the notches, whereinrotation of the dosing sleeve sets the dose by selecting a step.
 2. Theinjection device according to claim 1, wherein the length oflongitudinal shift of the shaft is between one step of the dosing sleeveand a shoulder of the injection device.
 3. The injection deviceaccording to claim 1, wherein the length of longitudinal shift of theshaft, also known the stroke distance, is defined by the movement of thestop between one step of the dosing sleeve and a shoulder of theinjection device.
 4. The injection device of claim 1, wherein the depthof one the notches on the shaft respectively corresponds to thelongitudinal length of one of the steps on the dosing sleeve.
 5. Theinjection device according to claim 1, further comprising a shoulderassociated with the device, whereby moving the advancing sleeve in onedirection causes the cam to contact one of the steps of the steppedmember, and whereby moving the advancing sleeve in the oppositedirection causes the stop to contact the shoulder, thereby providing aselected injection lift.
 6. An injection device for providing selecteddoses, wherein dose may be selected by the user of the device, thedevice comprising: an ampoule holder and a mechanism holder, themechanism holder holding an advancing sleeve, and a dosing sleeve forselecting the dose to be injected, said dosing sleeve disposed on themechanism holder, wherein the dose is selected by rotating the dosingsleeve relative to the mechanism holder, said dosing sleeve comprisingan operating element having a profile, an adjoining cylinder having adose imprint, a catch stop and a stepped member adjoining the sleeve,wherein the dosing sleeve, stepped member and cylinder generallysurround the advancing sleeve.
 7. An injection device of the typecomprising an ampoule receiving structure and a mechanism holderoperably coupled to the ampoule receiving structure, said injectiondevice comprising a dose selecting mechanism operably coupled to themechanism holder and comprising a dosing sleeve comprising an operatingelement having a profile, an adjoining cylinder having a dose imprint, acatch stop and a stepped member.
 8. The injection device according toclaim 7, wherein said mechanism holder generally contains an advancingsleeve, and wherein said dosing sleeve, stepped member and cylindergenerally surround the advancing sleeve.
 9. An injection devicecomprising: an ampoule holder in which an ampoule and a piston arelocated; a generally sleeve-shaped mechanism holder mechanically coupledto the ampoule holder; a longitudinally shiftable shaft is disposed Inthe interior of the mechanism holder to act on the piston; alongitudinally shiftable advancing sleeve generally surrounding andmechanically coupled to the shaft, the sleeve substantially closed atits free end by a lid; and a dosing sleeve for selecting a dose to beinjected carried on the mechanism holder and comprising a profiledoperating element, an adjoining cylinder with a dose imprint, a catchstop, and a stepped member.
 10. The injection device according to claim9, further comprising a cam disposed on the advancing sleeve, which,upon moving the advancing sleeve in the direction of the lid comes to astop against a step of the stepped member, and which, upon moving theadvancing sleeve in the opposite direction, comes to a stop against ashoulder carried by the mechanism holder, thereby providing a selectedinjection lift.
 11. An injection device for providing selected doses,wherein a dose may be selected by the user of the device, the devicecomprising: an ampoule holder and a mechanism holder, the mechanismholder holding an advancing sleeve, and a dosing sleeve for selectingthe dose to be injected, said dosing sleeve disposed on the mechanismholder, wherein the dose is selected by rotating the dosing sleeverelative to the mechanism holder, said dosing sleeve comprising anoperating element, an adjoining cylinder having a dose imprint, a catchstop and a stepped member adjoining the sleeve, wherein the dosingsleeve, stepped member and cylinder form a single unitary piece andgenerally surround the advancing sleeve.
 12. An injection device forproviding selected doses, wherein a dose may be selected by the user ofthe device, the device comprising: an ampoule holder and a mechanismholder, the mechanism holder having a generally central longitudinalaxis and holding an advancing sleeve, wherein the advancing sleeveaxially movable, and a dosing sleeve for selecting the dose to beinjected, said dosing sleeve disposed on the mechanism holder, whereinthe dose is selected by rotating the dosing sleeve relative to themechanism holder, said dosing sleeve comprising an operating element, anadjoining cylinder having a dose imprint, a catch stop and a steppedmember adjoining the sleeve, wherein the dosing sleeve, stepped memberand cylinder generally surround the advancing sleeve.
 13. An injectiondevice of the type comprising an ampoule receiving structure and amechanism holder operably coupled to the ampoule receiving structure,said injection device comprising a dose selecting mechanism operablycoupled to the mechanism holder and comprising a dosing sleevecomprising an operating element having a profile, an adjoining cylinderhaving a dose imprint, a catch stop and a stepped member, wherein thedosing sleeve, stepped member and cylinder form a single unitary piece.14. The injection device according to claim 13, wherein said mechanismholder generally contains an advancing sleeve, and wherein said dosingsleeve, stepped member and cylinder generally surround the advancingsleeve.
 15. The injection device according to claim 14, wherein saidadvancing sleeve is movable to a selected position and tends to remainin said selected position unless moved again.